[SystemZ] Tweak integer comparison code

The architecture has many comparison instructions, including some that
extend one of the operands.  The signed comparison instructions use sign
extensions and the unsigned comparison instructions use zero extensions.
In cases where we had a free choice between signed or unsigned comparisons,
we were trying to decide at lowering time which would best fit the available
instructions, taking things like extension type into account.  The code
to do that was getting increasingly hairy and was also making some bad
decisions.  E.g. when comparing the result of two LLCs, it is better to use
CR rather than CLR, since CR can be fused with a branch while CLR can't.

This patch removes the lowering code and instead adds an operand to
integer comparisons to say whether signed comparison is required,
whether unsigned comparison is required, or whether either is OK.
We can then leave the choice of instruction up to the normal isel code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190138 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 2 deletions

diff --git a/lib/Target/SystemZ/SystemZOperators.td b/lib/Target/SystemZ/SystemZOperators.td
index c89e315..c135b3b 100644
--- a/lib/Target/SystemZ/SystemZOperators.td
+++ b/lib/Target/SystemZ/SystemZOperators.td
@@ -15,6 +15,9 @@ def SDT_CallSeqEnd          : SDCallSeqEnd<[SDTCisVT<0, i64>,
                                             SDTCisVT<1, i64>]>;
 def SDT_ZCall               : SDTypeProfile<0, -1, [SDTCisPtrTy<0>]>;
 def SDT_ZCmp                : SDTypeProfile<0, 2, [SDTCisSameAs<0, 1>]>;
+def SDT_ZICmp               : SDTypeProfile<0, 3,
+                                            [SDTCisSameAs<0, 1>,
+                                             SDTCisVT<2, i32>]>;
 def SDT_ZBRCCMask           : SDTypeProfile<0, 3,
                                             [SDTCisVT<0, i8>,
                                              SDTCisVT<1, i8>,
@@ -94,8 +97,8 @@ def z_sibcall           : SDNode<"SystemZISD::SIBCALL", SDT_ZCall,
                                  [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue,
                                   SDNPVariadic]>;
 def z_pcrel_wrapper     : SDNode<"SystemZISD::PCREL_WRAPPER", SDT_ZWrapPtr, []>;
-def z_cmp               : SDNode<"SystemZISD::CMP", SDT_ZCmp, [SDNPOutGlue]>;
-def z_ucmp              : SDNode<"SystemZISD::UCMP", SDT_ZCmp, [SDNPOutGlue]>;
+def z_icmp              : SDNode<"SystemZISD::ICMP", SDT_ZICmp, [SDNPOutGlue]>;
+def z_fcmp              : SDNode<"SystemZISD::FCMP", SDT_ZCmp, [SDNPOutGlue]>;
 def z_tm                : SDNode<"SystemZISD::TM", SDT_ZCmp, [SDNPOutGlue]>;
 def z_br_ccmask         : SDNode<"SystemZISD::BR_CCMASK", SDT_ZBRCCMask,
                                  [SDNPHasChain, SDNPInGlue]>;
@@ -163,6 +166,16 @@ def z_prefetch          : SDNode<"SystemZISD::PREFETCH", SDT_ZPrefetch,
 // Pattern fragments
 //===----------------------------------------------------------------------===//
 
+// Signed and unsigned comparisons.
+def z_scmp : PatFrag<(ops node:$a, node:$b), (z_icmp node:$a, node:$b, imm), [{
+  unsigned Type = cast<ConstantSDNode>(N->getOperand(2))->getZExtValue();
+  return Type != SystemZICMP::UnsignedOnly;
+}]>;
+def z_ucmp : PatFrag<(ops node:$a, node:$b), (z_icmp node:$a, node:$b, imm), [{
+  unsigned Type = cast<ConstantSDNode>(N->getOperand(2))->getZExtValue();
+  return Type != SystemZICMP::SignedOnly;
+}]>;
+
 // Register sign-extend operations.  Sub-32-bit values are represented as i32s.
 def sext8  : PatFrag<(ops node:$src), (sext_inreg node:$src, i8)>;
 def sext16 : PatFrag<(ops node:$src), (sext_inreg node:$src, i16)>;